My half sister
by bakanishilovesyou
Summary: Before marrying James Potter, Lily had a fling with another muggle, resulting into Harry's half sister. I know this sounds weird, but I suck at summaries. Please read and review!  Negative comments are welcomed too.
1. Chapter 1

I do not own any of these characters except my own.

J.K.Rowling owns them. This takes place in fourth year.

Please read and review. Negative comments are welcome too. Sorry, I know I suck at summaries.

Rain poured down on innocent bystanders. Unfortunately, Thalia was one of the victims. She glanced down at the sheet of paper that was clasped in her fist. Rain drops had made the spiky black handwriting incorrigible. She willed herself to look at it, and tried to read the address. She could vaguely make out the starting of an H, O, and an S, but that didn't seem to help. She opened her duffel bag that was swinging over her shoulder, and grabbed the map she had bought.

It was faded and yellow, but at least it wasn't incorrigible. Judging from where she was standing now, she should be able to reach her destination in ten minutes. What am I doing this anyway? Thalia thought to herself. She perfectly knew that even by going there, she maybe unwelcome and probably even hated for attending this school. This thought had stopped her from attending Hogwarts for four years, preferring to study alone with some private tuition from all the Hogwarts teachers. But today, she had contacted Dumbledore, and he had agreed to let her join Hogwarts from today onwards. She trudged along the muddy path, and her shoes seemed to squeak in protest. As she reached a desolate building with a sign on a stake that said, "DANGER-KEEP OUT."

Thalia knew that she was here. As soon as she walked on the path, the building turned to a magnificent castle, with two large doors with brass knockers. Thalia reached for those brass knockers and hesitated. She wondered if her half brother had been informed. She wondered if he was angry. She opened her bag and reached for the folded letter, which was so old that it looked prehistoric. She knew this letter would explain everything. Maybe I shouldn't have come here after all. Thalia thought to herself silently. Just then, her stomach growled. Thalia could faintly smell roast potatoes and steak that was travelling from the inside of the castle. She was wet and hungry. She could just go in. Yet, another part of her brain seemed to retort, what if nobody liked her? After what seemed like a never-ending debate with each parts of her own brain, she reached for the brass knockers and knocked on the door. The doors creaked opened, and Thalia peered into the castle anxiously. There were rows and rows of tables, with different coloured banners hanging from the top.

She recognized the enchanted ceiling and the different houses, as she had read _Hogwarts: a History _a thousand times before she had arrived. She pushed the door slightly further and noticed Dumbledore and the others seated at another table. Dumbledore seemed to have noticed her and beckoned her in. Almost instinctively, she reached for her hood and covered her face as she walked towards the table. All eyes were on her and she quickened her pace. Dumbledore cleared his throat and started to speak. "As you all know, Harry Potter's mother is called Lily Potter. Well before she married James Potter, she had er- what you call a short fling with another muggle man." The whole hall seemed silent and Thalia didn't dare to raise her head. Dumbledore blazed ahead, "Well, Lily apparently was distraught when she found out that she was pregnant, and at that time, she was about to marry James already. Hence, she gave her daughter, which she named Thalia, to the muggle man. Unfortunately, he was killed in a car accident a year ago. So, I have teaching Thalia for the past four years, and I have decided she has enough experience to enroll in Hogwarts." Nobody seemed to move and Thalia squirmed uncomfortably. "She has already been sorted to Gryffindor, so I hope all of you will welcome her warmly."

Dumbledore said, and he resumed eating his pudding. The others followed suit and Thalia walked to the Gryffindor table and sat down, keeping her hood on. The boy with flaming red hair who was sitting across her seemed to be in a state of shock and kept nudging a boy with messy black hair who was sitting next to him. The boy with the messy black hair spoke first. "Errmm- Hullo." Thalia managed to nod and tried to focus on eating her pudding. "So… I guess you are my half sister?" The boy said. Thalia seemed to have frozen in her seat. So… That meant the person sitting across her was Harry Potter? Her half brother? She lifted her head and glanced at him. With a jolt, she recognized the familiar features that she possessed. The green eyes, the black hair. The only difference was his long thin scar on his forehead. "Hi." She managed and took off her hood. It was a bad idea. Everyone stared, and she was certain she could hear them whispering. She opened her bag and gave the letter to Harry, who seemed to be frozen solid. "Errmm thanks." He said and stuffed the letter into his bag. Thalia managed a faint smile and proceeded to her pudding.

So that was how famous Harry Potter's half sister did the whole time during dinner. Focusing herself on eating pudding.


	2. Chapter 2

Author's note: Thanks to all the people who commented. :D

I really appreciated it and thanks for all the advice too.

CHAPTER TWO IS NOW UP!

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Chapter two

Light shone into the girl's dormitory, illuminating on each of their faces. Everyone was still asleep. Nobody woke up at the crack of dawn.

Except someone.

Thalia stared at the wall in front of her. She couldn't sleep. The words Dumbledore had said was echoing in her head. She closed her eyes, trying to get control over the bizarre situation.

She tried to hold back the tears that threatened to erupt from her, but she couldn't help it.

Tears flowed down her face, and Thalia held back a sob. She hated them. She didn't understand why she was thrown aside by her mother. She knew that her mother was about to marry James Potter, yet she couldn't help but resent all of them.

The hatred she held in her heart felt like it could burst. Her mother didn't even bother to visit her. She had distanced herself from her muggle father, preferring to keep a distance. Year after year, they drifted further apart.

And that year. When he died… Thalia didn't feel like crying. She had used up a life time supply of tears crying about her mother.

She could vaguely remember an early memory when she had asked her father innocently about her mother.

"Daddy, how come Lizzie has a daddy and a mummy, but I only have you?"

That question echoed in her head, and Thalia managed to chuckle to herself.

At that time, her innocence seemed refreshing. Her father had always avoided that subject, yet, as a seven year old, she had never suspected anything.

Thalia glanced at the flames, trying to understand what it all meant. Was the gods playing a joke on her? Or was it destined in the stars for Thalia to get shunned aside, to be tormented for her whole life?

"All this thinking is giving me a headache." She muttered to herself and got up from the armchair. She was in the Gryffindor common room alone.

Nobody else had gotten up yet and Thalia stretched her arms over her head and yawned lazily. The night she spent in the girl's dormitory was hell. She couldn't sleep, and visions of herself being teased and tormented mercilessly came every two seconds.

Her stomach grumbled and she wondered if breakfast could be served earlier. She had already changed into her robes an hour ago. She walked out of the common room, trudging down the steps warily. Was it against the rules to get breakfast early?

She reached the ground floor and navigated to the Great hall when she heard footsteps. She stopped momentarily. Was she even allowed to be here at six a.m in the morning?

Thoughts raced past in her head and Thalia immediately ducked behind a pillar, hoping that whom she would see would be a friendly face. "Meow." A cat purred and Thalia froze. That cat looked familiar. Dumbledore had mentioned a cat who helped the caretaker in Hogwarts. Was it Mrs Tibbles or Mrs Dumbo or something like that?

"Shoo, kitty, shoo!' The cat stayed where it was, glaring at her with it's large black eyes that looked like it contained no warmth. "What do we have here?" A raspy voice asked.

Thalia could have hit herself. That stupid cat's name was Mrs Norris! And that meant that she was caught by Argus Filch.

She spun around. "Urmm... Hi?" She said, waving her hand.

"You are in big trouble now, Potter!" He said, practically laughing with glee.

Anger burned in Thalia's insides, and she retorted, "I may be his half sister, but my last name isn't Potter, Filch. Or is it Filth?" She said mockingly.

Filch turned positively purple.

"Wait- I got it now. It's squib right?" She said, pretending to think hard.

Filch seemed to explode. "POTTER MUST HAVE TOLD YOU THAT RIGHT? HE THINKS HE IS SO SMART! WELL, MS. - WHATEVER IS YOUR LAST NAME, YOU ARE GOING TO SPEND DETENTION SCRUBBING THE HOSPITAL BEDS!"

"Yeah yeah." She said. And walked back to the dorm. It wasn't until she reached the Gryffindor common room, when she realised that she was in big trouble.

Her second day at Hogwarts was already a disaster.


	3. Chapter 3

None of these characters belong to me, except for Thalia.

Thank you for all the comments and words of encouragement.

CHAPTER THREE IS NOW UP!

(Sorry for the short chapter 2.)

A few miles away from Hogwarts, in an old and abandoned shack, lay a pale and skinny man.

He looked rather odd as he had extremely pale skin, red eyes and small slits for his nose. He was seated on an armchair in front of a roaring fire, enjoying the warmth.

Another man, who was short and stubby, was kneeling in front of the pale and skinny man. He had lost a finger and seemed to be pleading for mercy.

The pale and skinny man was none other than the notorious dark wizard, Lord Voldermort. The other man, who was on his knees, was his follower, Wormtail.

"You have failed me yet again, Wormtail." Voldermort hissed, and Wormtail trembled, his voice coming out in squeaks. "But my Lord, we do not need the boy! I could simply-." He was cut off my Voldermort who threw him a venomous look.

Voldermort stood up and spoke, his voice echoing around the abandoned shack. "Wormtail, remember what I told you at the start of this year?"

Wormtail trembled uncontrollably, and uttered a single word. "Yes." Voldermort stared at his follower, as if to challenge him. "What did I tell you then?" He asked.

"You told me to keep an eye on Potter. You said somebody related to Potter is coming. You said to use her as a pawn." Wormtail recited. "Precisely, Wormtail." Voldermort said, as he glanced out of the tiny window.

Voldermort continued his speech, ignoring Worm tail's muttering and trembling. "We must find out her weakness, and then we can capture her, use her. Potter would surely come to save her. Then- we have him." He announced, crushing his fist as if Harry Potter was inside it.

"So, Wormtail, you must not fail me now. Go according to the plan. If not- You know what will happen." Upon hearing this, Wormtail threw himself at Voldermort's feet, sobbing and trembling.

"No master, please! Have mercy…" He croaked.

Voldermort stared at him with disgust. "Get up you pathetic piece of vermin." He hissed, practically spitting. Wormtail acted on his instructions and stood up uncertainly.

"Go and initiate the plan now." Voldermort rasped as he glanced over his shoulder, looking at the blood-red sunset, as Wormtail whimpered once more and left.

Over at Hogwarts. 

Thalia slumped onto the ground, in daze. She had detention already? And it was only her second day at school. "Stupid cat." She grumbled and lifted herself up.

"Who are you talking to?" A voice rang out from the other side of the common room and Thalia fell back onto the ground in fright.

"Hey- Who do you think you are? It's not funny to scare someone out of her wits. Especially when she is talking to herself, you evil-." She glanced up to look at her "attacker" and stopped momentarily.

It was Harry.

Shoot. Of all times, did it have to be her half brother? She nearly called him an evil cockroach. She gulped and forced a smile on her lips.

"Oh, it's you. Hi." She said flatly. She was in no mood to entertain him by acting over-enthusiastic. "Evil what?" He asked, a glint in his eye. "No one. Errmm.. Slip of a tongue!" She said, laughing nervously and edging to the girls dormitory.

"Oh, okay." He said and an awkward silence filled the air. Thalia sighed. "Look, if you don't want to talk to me, just say it." She said flatly, as to prove a point.

Harry's head jerked up. "Huh? Not talk to you? I didn't mean that!" He protested, and Thalia stifled a laugh. "So… Why are you ignoring me?" She pressed on, as she traced the pattern on the girl's dormitory steps with her finger. Harry remained silent.

After what seemed like eternity, he finally spoke up. "I just found it weird. I didn't my mum had flings everywhere." He said, and looked away quickly.

Thalia squirmed uncomfortably. "Well, I guess she couldn't help it." She mumbled. "Yeah, I suppose so." He said quietly and the silence fell over the once again.

Thalia spoke first. "Why don't we start again. Let's just pretend I am completely unrelated to you and we are just friends. How about that?" She asked tentatively.

Harry stared at her in what seemed like disbelief. She stared back at him anxiously. To her relief, he nodded and stretched out his hand.

She grinned and shook his hand and Harry smiled at her faintly before launching into a conversation that ranged from Quidditch to lessons. Thalia had told him privately what she had said to Filch.

She had expected him to shake his head and tell her she was in big trouble. What she didn't expect him to do was to laugh uproariously.

"What's so funny about that?" She said indignantly. He snickered and shook his head. "Hey, it's late already. Lessons are starting soon and I still need to wake Ron. See you later?" Harry asked. " Yup." She replied and headed up to the girls dormitory, hoping to be able to sleep for at least twenty minutes.

She jumped onto her bed and closed her eyes. She was about to drift off to deep sleep when someone's alarm clock rang. Everybody started scrambling out of their beds and Thalia groaned.

"I hate these stupid rules to all eat breakfast at the same time." She grumbled and got out of her bed, awaiting for the challenges the day would bring her.


	4. Chapter 4

Note from Author: Thank you for all your comments and story alerts:D (A bit of Draco bashing in this chapter. SORRY!)

I do not own any of these characters except for Thalia.

CHAPTER FOUR IS NOW UP!

Thalia forced herself out of the comfortable bed and trudged down the steps grumpily. She didn't even get to sleep for five minutes.

As she reached the bottom of the steps, she was greeted by Harry and his friends, who Harry had introduced a few minutes later. She nodded in acknowledgement grumpily. She was deprived of her sleep, and she was extremely hungry.

The walk down to the Great hall was slightly more different than what Thalia had expected. She had expected that Ron and Hermione would ignore her; instead, they talked to her like it was no different than any other day.

Thalia was slightly bewildered by her good luck and remained silent on her way down.

Her peace was interrupted minutes later when a pale boy with platinum blond hair cornered them. "Potter's sister? Ha! Do you have a foul scar on your forehead too?" Thalia was in no mood to retort. She was seriously deprived of her sleep and her stomach was growling. "Shut up Malfoy." Harry retorted and Thalia noticed that he was reaching for his wand.

Both Harry and Malfoy were glaring at each other; both of them looked like they were itching for a showdown. "Harry, don't use magic against him. You will be breaking the rules." Hermione hissed, and Thalia watched as Harry pocketed his wand.

"Too scared, Potter? Taking orders from a mud blood?" He taunted and Thalia felt a burning sort of anger in her stomach. She knew she shouldn't behave on impulse, but in a few seconds, she had pushed herself out of the crowd, and aimed a swift punch at Malfoy's nose.

"OW! YOU B-!" He yelled, and Thalia felt the urge to punch him on his nose again. "Wow, you are a sissy. Seriously, it's just a broken nose. Or maybe, I could call mummy to come and pick you up?" She asked sarcastically. "Wait until my father hears about this!" Malfoy barked and escaped the scene.

"You stupid dirty cockroach! Are you threatening me? I swear I will beat up your ugly pug face next!" She yelled to his retreating back.

She glanced back at the threesome and she had to stifle a laugh as she noticed each of their different reactions.

Harry was grinning widely, Ron was staring at her in awe, but Hermione looked disapproving and tried to convince Thalia not to use violence in the Hogwarts the whole time during breakfast.

"Seriously Thalia. You could even get suspended-.." Thalia wasn't really listening, but nodded distractedly as she chewed on her eggs. "Give it a rest Hermione." Harry said, as he loaded his plate with sausages.

Hermione looked flustered as she glared at both Harry and Ron angrily, who were both too absorbed with their food. "Are you going to eat those eggs?" Thalia asked and Hermione rolled her eyes as she piled up her plate with more food.

"Seriously. They are exactly alike." Hermione muttered under her breath and Thalia decided to ignore this to enjoy her breakfast.

"Miss Jones. Here is your timetable." Thalia glanced up and noticed Professor McGonagall staring down at her, a sheet of paper in her hand. "Tanks." Thalia replied, her mouth full of eggs.

She stuffed her timetable in her bag and listened to Harry and Ron argue continuously about Quidditch teams.

Thalia resisted the urge to join in and ate her breakfast hastily. It was her first day of lessons and she didn't want to be late. She waited for the others to be finished with their breakfast before walking out of the hall for Charms lessons.

Professor Flitwick was seated on a large pile of books. There were a raven or either a toad on each desk and everyone found their seats and sat down.

After some consideration, Thalia decided to pair up with Ron for that day's charms lessons. It was a bad idea.

Thalia couldn't silence her raven and Ron had prodded his toad over the desk and it was instantly squashed by Seamus who was sitting in front of them.

Professor Flitwick was not pleased, but he still gave another toad to Ron. After several attempts, Thalia managed to silence her raven, which irritated her greatly as it had nipped her finger twice.

"I'm bringing plasters for the next charms lesson." She said flatly, as she glanced at her bleeding fingers.

"I thought that was a really useful charms lesson." Hermione said and she proceeded to explain something that didn't sound remotely like English.

"Sorry Hermione, but can you not explain all this in Greek?" Thalia asked grumpily. Hermione didn't seem fazed by her comment, and continued talking at the speed of lightning.

"You'll get used to this." Harry said, patting her back before catching up with Ron.

"Get used to this? Not likely." She muttered to herself and braced herself for torture as she entered the dungeons for Potions lessons.


	5. Chapter 5

Author's note: I am so sorry that I didn't update sooner. :0

Thank you for all the comments, story alerts and favourite stories.

Also, a special thank you to my LJ friend, Desirae1985 for the idea.

The next two chapters will be dedicated to the Yule ball, due to the Author being on crack.

Sorry! 

Potions lessons did not prove to be satisfactory. Professor Snape had passed by her cauldron twice, commenting on how poor Thalia's potion work was.

The potion that was supposed to be a shade of vibrant yellow had changed into a shade of beetroot red, and Thalia was feverishly throwing in random ingredients to turn her potion yellow.

"Stupid potion. Stupid teacher. Stupid stupid-" With every word, Thalia threw in a random ingredient, and her potion was bubbling faster, threatening to spill out.

It was only when she stopped cursing, when she realised her potion was bubbling extremely quickly and it was overflowing. "Oh crap." She muttered under her breath and glanced into her cauldron to access the situation.

As she glanced into the pot, she gulped. The potion was now a dirty shade of black, bubbling quickly in her cauldron. "Hermione. I need some help here!" She hissed as she tugged on Hermione's dress robes.

"What?" She snapped as she glanced into Thalia's cauldron. "What did you put in there?" She said, poking her wooden spoon in and scooping up a sample of the black liquid.

"Urm… No idea?" Thalia said weakly. "Time's up." Professor Snape's voice echoed around the room as he sat on the chair behind his desk. "Hand in your potions." With a sinking heart. Thalia scooped a portion of the black liquid and poured it into the bottle.

"Very poor, Miss Jones. Tut, tut, this doesn't even look like the dream potion I had requested. P for your work." He said dryly before proceeding to look at Hermione's potion, which was a nice shade of yellow.

Thalia rolled her eyes and waited for Harry and Ron to hand in their potions before all of them proceeded down the steps to the great hall for lunch.

"What grade did you get for potions?" Hermione asked eagerly. Thalia ignored her question and instead, tried to focus her attention on walking down the steps.

"I got an A. It isn't too good but Professor Snape-" "Shut it will you?" Ron snarled and Hermione fell silent. Thalia had a hunch that Ron didn't do too well for his potions either and proceeded down to the Great hall in silence.

As they walked into the Great hall, they were greeted by the smell of roast beef and boiled potatoes. Thalia took a large serving of potatoes and plopped herself onto her seat and ate hastily.

But at that moment, Dumbledore walked in, and a hushed silence fell over the room. He sat down on his chair and cleared his throat. "As you all know, on certain years, there is a ball." He glanced around the hall and began again, "This tradition was stopped after a period of time. But this year, the ministry has agreed to continue the Yule ball, hence there will be a ball this year."

"You are allowed to come with a dance partner. You will also be allowed to wear your dress and dress robes there. It will be held on the sixteen of November, which is exactly a week from now." He scanned the room once again, and spoke. "For more details, please approach the head of your house." He said, and departed from the great hall.

The minute he left, everyone started whispering and discussing about the Yule ball. "Great, I don't have a dress." Thalia moaned, as she poked her boiled potatoes with her fork.

"Are guys supposed to ask girls?" Hermione asked and Harry shrugged, too busy looking at Cho Chang, who was sitting at the Ravenclaw table.

"Earth to Harry." Thalia teased as she nudged him playfully, resulting him to spit out his boiled potato. "Watch it!" He yelped. "Who are you planning to ask, mate?" Ron asked, stuffing his face with the roast beef.

"I don't know." Harry mumbled. "Yeah right. It's Cho Chang you want to ask right?" Thalia said as she took another bite of her potato.

Harry dropped his spoon with a clatter, and she could vaguely see him blushing under the table as she groped for the spoon.

"Seriously, all of you. We are going to be late for classes!" Hermione exclaimed as she grabbed her bag and prepared to leave. "Alright, alright. Give it a rest." Thalia mumbled as she threw her green duffel bag over her shoulder and they left to their classes hastily.

After dinner in the girls dormitory.

Screams and squeals could be heard in the girl's dormitory as dozens of girls tried on many sorts of dresses, ranging from colourful to dull. Thalia did not participate in that activity, preferring to just watch as Hermione traded and changed outfits repeatedly.

"Honestly, I have no idea what to wear. How can you be so relaxed?" Hermione babbled on and Thalia pretended to listen. "I already know what to wear anyway." She said flatly. "Really? Could I see?" Hermione asked while attempting to squeeze into a pale lavender dress.

"I'm wearing my hoodie and jeans." She said, shrugging as she watched Hermione try on a lime green dress next.

"What? You can't wear that!" She shrieked as she pulled on an elegant black dress next. "You have to wear a dress." She said. "Sheesh, could I just wear a skirt? Dresses make me itch."

Hermione sighed as she sat on the pile of ever growing clothes. Thalia grinned and pulled out a hot pink dress from the pile. "I think this looks nice on you. I think you should wear this." She proclaimed. Hermione gave a fleeting look at it before smiling faintly and putting it over her head.

The dress fell nicely over her knees. "Wow." She gasped softly. "I told you." Thalia said as she looked at Hermione.

Hermione grinned and took off the dress. "Thanks." She said and folded it neatly into her trunk.

"Anytime." Thalia said as she watched an ecstatic Hermione leave the tiny bathroom, whistling happily.

Her smile faded of her face and Thalia knew that this was going to be her biggest dilemma yet.


End file.
